Climate Change (module 6)

Question 1

Describe how carbon is transferred among Earth’s spheres in the carbon cycle, especially the lithosphere, atmosphere, and biosphere

Answer 1

atmosphere - carbon mainly stored as CO2 and CH4
bioshpere - plants take in CO2, animals exhale CO2, decaying organic matter releases CO2, burning plants release CO2, animals release CH4
lithosphere - carbon is held in the soil, in carbonate rocks, and other materials like coal
hydrosphere - carbon dissovles in the water to form carbonic acid
cryoshere - carbon is stored in permafrost (frozon soil), and as CO2 and in Ch4 gas in bubbles in ice

Question 2

Describe changes in fossil-fuel carbon emissions from 1959-2014

Answer 2

• Increasing in magnitude
• rapid increase from 1959-1980’s
• relatively stable from 1980-2000
• emission intensification from 2000-2014

Question 3

Describe changes in the uptake of carbon by the atmosphere, oceans, and terrestrial biosphere from 1959-2014

Answer 3

atmosphere - increased, with some years where there has been decreases
oceans- increases but relatively stable
terrestrial biosphere - increased, land-use changes, deforestation have released large amounts of carbon - 1987 forest fires

Question 4

Explain why the atmospheric CO2 concentration changed over the past 50 to 60 years

Answer 4

• Fossil fuel combustion - more CO2 emission, increase in atmospheric CO2 concentration
• Deforestation and Land-use changes - reducing earth’s capacity to absorb and store carbon
• Industrial processes - cement production release CO2 and other greenhouse gases

Question 5

Describe how greenhouse gases affect Earth surface temperatures

Answer 5

• infrared radiation passes through the atmosphere but most is re-absorbed and re-emitted in all directions by greenhouse gas molecules and clouds
• the effect of this is to warm Earth’s surface and the lower atmosphere
• solar radiation powers the climate system
• about half the solar radiation is absorbed by the Earth’s surface and warms it
• some solar radiation is reflected by the Earth and atmosphere

Question 6

Explain the natural and human-enhanced greenhouse effect

Answer 6

Natural - Solar radiation -> re-radiated heat -> less re-emitted hear -> more heat escapes into space
Human-enhanced (more greenhouse gases) - Solar radiation -> re-radiated heat -> more re-emitted heat -> less heat escapes into space

Question 7

Identify the control variable and planetary boundary for climate change

Answer 7

• Atmospheric CO2 concentration (ppm) - 350ppm CO2 (current 425 ppm)
• Energy imbalance at top of atmosphere W/m2 - 1W/m2 (relative to pre-industrial levels) - current 2.3 W/m2

Question 8

Identify evidence for a changing climate change

Answer 8

• Warming air temperatures
• warming ocean temps
  -rising sea levels
  -shrinking glaciers and sea ice
  -changes in biosphere
• > 90% of extra heat in the climate system is absorbed by the oceans

Question 9

Identify the actions that we need to take to reduce future global warming

Answer 9

• low global emissions of CO2
• live car free
• upgrade light bulbs
• wash clothes in cold water
• eat a plant based diet
• travel less by plane